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(BaTiO 3 –SrTiO 3 )/(WO 3 ) x ceramics with x  = 0 up to 5% were synthesized using solid-state reaction via high-energy ballf milling technique. Various characterization techniques were used including X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform-infrared spectroscopy (FT-IR), and UV–visible diffuse reflectance (DR) spectrophotometer. Structural analysis via XRD indicates the formation of two separate phases of SrTiO 3 (STO) and BaTiO 3 (BTO) having both cubic structures. The presence of BaWO 4 as impurity was detected for higher concentration. SEM observations show a reduction in the average grains size with increasing WO 3 addition. In comparison with free-added ceramic, the optical band gap energy ( E g ) shows a slight increase with WO 3 addition. Contextual investigations on the electrical and dielectric properties of various WO 3 added to BTO–STO ceramics have been used to evaluate conductivity ( σ ), dielectric constant and loss ( ε r ′ and ε r ″ ), and dissipation factor ( t a n δ ) against both frequency and dc bias voltages. Generally, both σ and ε r ″ correspond to the tendency of the power law to frequency. However, dc bias has been noticed to be lesser affecting the conduction mechanisms, which has a small variation for various WO 3 addition ratios. In addition, the dissipation factor was found to be highly dependent on both the addition ratio and the frequency as well as dc bias applied.

RAC1 activity is critical for intestinal homeostasis, and is required for hyperproliferation driven by loss of the tumour suppressor gene Apc in the murine intestine. To avoid the impact of direct targeting upon homeostasis, we reasoned that indirect targeting of RAC1 via RAC-GEFs might be effective. Transcriptional profiling of Apc deficient intestinal tissue identified Vav3 and Tiam1 as key targets. Deletion of these indicated that while TIAM1 deficiency could suppress Apc- driven hyperproliferation, it had no impact upon tumourigenesis, while VAV3 deficiency had no effect. Intriguingly, deletion of either gene resulted in upregulation of Vav2 , with subsequent targeting of all three ( Vav2 −/− Vav3 −/− Tiam1 −/− ), profoundly suppressing hyperproliferation, tumourigenesis and RAC1 activity, without impacting normal homeostasis. Critically, the observed RAC-GEF dependency was negated by oncogenic KRAS mutation. Together, these data demonstrate that while targeting RAC-GEF molecules may have therapeutic impact at early stages, this benefit may be lost in late stage disease. Loss of small GTPase RAC1 suppresses intestinal tumorigenesis caused by APC loss, but impacts normal intestinal homeostasis. Here, the authors provide an alternative method of reducing RAC1 activity by the combined targeting of three RAC-GEFs and show that this approach delays intestinal tumorigenesis without the detrimental effects on normal intestinal architecture.

In this study, a series of SrGa 0.02 Fe 11.98 O 19 -Zn 0.5 Ni 0.5 Fe 2 O 4 hard/soft nanocomposites (SrGaFeO-ZnNiFeO H/S NCs) were synthesized via a single-pot (citrate sol–gel) approach by applying different calcination temperatures. The electrical and dielectric properties of the SrGaFeO-ZnNiFeO H/S NCs based on the calcination temperatures in between 800 and 1100 °C were systematically investigated with an impedance analyzer of up to 3.0 MHz frequency and within 20 and 120 °C temperature range. Both electrical and dielectric parameters, such as ac/dc conductivity, dielectric loss, dielectric constant, and tangent loss, were measured for a given calcination temperature. It has been found that AC conductivity generally conforms the power law rules, largely dependent on calcination temperatures. Impedance analysis has observed that the conduction mechanisms of SrGaFeO-ZnNiFeO H/S NCs at various calcination temperatures are mainly attributable to grain–grain boundaries. The dielectric constant of SrGaFeO-ZnNiFeO H/S NCs shows normal dielectric distribution with frequency, largely dependent on calcination temperatures. Ultimately, the observed change in dielectric properties with frequency can be attributed to the conduction mechanism in most compound ferrites, which can be phenomenologically explained by Koop’s model.

The Nb3+ ion substituted Sr hexaferrites (SrNbxFe12−xO19 (x = 0.00–0.08) hexaferrites (HFs)) were fabricated via a citrate-assisted sol-gel approach. X-ray powder diffractometer analysis affirmed the pureness of all products. The crystallite sizes of the products which were estimated from Scherrer equation were in the 36–40 nm range. The chemical component of the samples was proved by Energy-dispersive X-ray spectroscopy (EDX) and Elemental mapping. The hexagonal morphology of all products was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM). The electrical conduction mechanisms and dielectric properties of a variety of Nb3+ions-substituted SrNbxFe12−xO19 HFs were investigated by a complex impedance system. Dielectric parameters such as conductivity, dielectric constant, dielectric loss, dielectric tangent loss and complex modulus, were studied at temperatures up to 120 °C in a frequency range varying from 1.0 Hz to 3.0 MHz for several Nb ratios. The frequency dependence of the conductivity was found to comply with the power law with diverse exponents at all frequencies studied here. Subsequently, incremental tendencies in dc conductivity with temperature indicate that the substituted Sr-HFs leads to a semiconductor-semimetal like behavior. This could be attributable to a feature of conduction mechanism which is based on the tunneling processes. Additionally, the dielectric dispersion pattern was also explained by Maxwell–Wagner polarization in accordance with the Koop’s phenomenological theory.

A functionalized multiwall carbon nanotube (MWCNT)–COOH/Fe 3 O 4 hybrid was fabricated by co-precipitation method. Fe 3 O 4 nanoparticles were stably attached to the surface of carboxyl groups (COOH). The presence of Fe 3 O 4 nanoparticles and their surface conjugation to MWCNT have been confirmed by XRD, TEM and FT-IR techniques. Magnetic evaluation revealed a superparamagnetic character of the hybrid and therefore the attached Fe 3 O 4 nanoparticles. The crystallite size (9 ± 3 nm), particle size (9 ± 2 nm) and magnetic domain size estimated for Fe 3 O 4 are consistent with each other, which reveal the single crystalline character of the nanoparticles. Electrical conductivity and dielectric behavior have also been characterized by utilizing impedance spectroscopy up to 3 MHz for an isotherm line varying from 293 to 393 K by 10 K steps. Electrical characteristics and its complex dielectric approaches might be elucidated with the existence of a conventional tunneling conduction mechanism of temperature-independency. The AC conductivity of MWCNT–COOH/Fe 3 O 4 hybrid could also be a consequence of the estimations of the universal dynamic response.

Background: It is believed that health risks associated with smokeless tobacco (ST) use are lower than those with cigarette smoking. A systematic review was therefore carried out to summarise these risks. Methods: Several electronic databases were searched, supplemented by screening reference lists, smoking related websites, and contacting experts. Analytical observational studies of ST use (cohorts, case-control, cross sectional studies) with a sample size of ⩾500 were included if they reported on one or more of the following outcomes (all cause mortality, oral and pharyngeal cancers, other cancers, cardiovascular diseases, dental diseases, pregnancy outcomes, surgical outcomes). Data extraction covered control of confounding, selection of cases and controls, sample size, clear definitions and measurements of the health outcome, and ST use. Selection, extraction and quality assessments were carried out by one or two independent reviewers. Results: A narrative review was carried out. Many of the studies lacked sufficient power to estimate precise risks, mainly due to the small number of ST users. Studies were often not designed to investigate ST use, and many also had major methodological limitations including poor control for cigarette smoking and imprecise measurements of exposure. Studies in India showed a substantial risk of oral or oropharyngeal cancers associated with chewing betel quid and tobacco. Studies from other regions and of other cancer types were not consistent. Few studies have adequately considered the non-cancer health effects of ST use. Conclusions: Chewing betel quid and tobacco is associated with a substantial risk of oral cancers in India. Most recent studies from the US and Scandinavia are not statistically significant, but moderate positive associations cannot be ruled out due to lack of power. Further rigorous studies with adequate sample sizes are required, especially for cardiovascular disease.

Ce and Y substituted SrFe 12 O 19 (x = 0.4 and 0.5) nanohexaferrites have been synthesised by sol–gel auto-combustion. The pure hexagonal SrFe 12 O 19 phase was confirmed by XRD, FE-SEM and HR-TEM. The ac conductivity and dielectric properties of Ce and Y substituted Sr:Fe 12 O 19 nanohexaferrites were studied by using complex impedance technique. Dielectric properties such as dielectric constant, dielectric loss, dielectric tangent loss, as well as ac conductivity are measured at various bias potentials in a varying frequency range from 10 Hz to 10 MHz. The frequency dependency of the ac conductivity could be evaluated by a power exponent law at higher frequencies, which is a characteristic mechanism for electrical charge transport by tunnelling processes with which it is more dispersive at lower frequencies. The conduction mechanisms were also investigated at various dc bias potentials, mainly being an indicative of hopping type conduction. So, the dielectric dispersion behaviour can be well elucidated in terms of Maxwell–Wagner polarization in accordance with the Koop’s phenomenological theory. Utilizing an electrical equivalent circuit model, impedance studies were carried out in a specific frequency domain to characterize all the contributions of the dielectric response between the grains and grain boundaries to the dielectric parameters.

The electrical and dielectric properties of Y3Al5O12 (yttrium aluminum garnet, YAG) ceramics are investigated in detail. YAG:(Yb)x (0.01 ≤ x ≤ 0.09) was synthesized by a solid state reaction and characterized by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The electrical and dielectric properties have been intensively studied under certain bias voltages up to a frequency of 10 MHz. These properties are dependent on the substitution rates, independent of the bias voltages. The experimental result shows that Yb3+ ion substitution into YAG ceramics significantly influences the conductivity, dielectric constant, and lossy mechanisms, which is probably owing to the 3d-Al ions and 4f-Yb ions incorporated at different positions of structural symmetries in Y3−xYbxAl5O12 (0.00 ≤ x ≤ 0.09) ceramics.

This study reported the effect of Eu substitutions on the conductivity and dielectric properties of Y3−xEuxAl5O12 (0.0 ≤ x ≤ 0.1), YAG:xEu3+. All products were fabricated by solid state route. The formation of YAG was approved through X-ray diffraction powder diffraction and high-resolution transmission electron microscope. It was found that the lattice parameters are increasing with increase the substitution content due to the difference in ionic radii between Y3+ and Eu3+. Electrical and dielectric properties of YAG (Y3Al5O12) and YAG:xEu3+ ceramics were investigated extensively for a variety of concentrations (0.00 ≤ x ≤ 0.1) of the substitutional Eu3+ ion from the 4f lanthanide group. The temperature dependence of dielectric loss, dielectric constant, loss tangent and ac/dc conductivity were examined up to 5.0 MHz to understand the electrical and dielectric properties for both doped and undoped YAG ceramics. The experimental results revealed that Eu3+ ion substitutions (especially x = 0.05) in YAG ceramics meaningfully influence the lossy mechanisms, conductivity and dielectric constant which is probably due to the contribution to the conduction mechanism of the 4f–Eu and 3d–Al ions. So, this can be incorporated at the exceptional sites of both Oh (octahedral) and Td (tetrahedral) symmetries in YAG: xEu3+ ceramics.

The aim of the study was to investigate some physiological effects of an insecticide (Akira 20-SP) with acetamiprid agent on Cin misir Adapop 10 and Sert misir Adapop 2 cultivars of corn plants in different concentrations [0 g/L, 0.6 g/L (recommended concentration), 1.2 g/L]. Photosynthetic pigment substances, total soluble protein and proline contents were determined. Analysis of treated leaves showed that the recommended concentration resulted in higher chlorophyll value in Cin misir Adapop 10 and Sert misir Adapop 2. Carotenoid amounts increased in Cin misir Adapop 10 and decreased in Sert misir Adapop 2 to the control. Total protein contents decreased in x2 recommended concentration in Cin misir Adapop 10 and in all treatment groups in Sert misir Adapop 2 and proline amounts significantly increased in proportion to the increasing concentration in both cultivars. Especially high concentrations of acetamiprid affect plant metabolism of both cultivars negatively.